Add ability to auto convert a foreach loop over a query to IJobEntity

Basically add a code action to transform something like:

```cs
foreach(var (RefRO a, RefRW b, Entity entity) in SystemAPI.Query, RefRW>().WithEntityAccess() {
...
}
```

to

```cs
internal partial struct JOB_NAME: IJobEntity {
private void Execute(in ComponentA a, ref ComponentB b, Entity entity) {
...
}
}
```